The state of the art in video technology has been advanced in recent years with the introduction of large scale video displays based on television techniques. For example, the videowall concept, known for several years in the prior art, employs a large plurality of color cathode ray tubes disposed in a matrix, with image signals apportioned among the individual cathode ray tubes so that the entire matrix may display a single, large image, or various groups of tubes may display separate images, or the like. Such displays are extremely effective in creating moving image displays for entertainment and information purposes, and have found wide acceptance in convention halls, sports arenas, stadiums, and advertising display signs.
One drawback of the multiple television tube display is that the outer border of each tube cannot project any light, due to the physical limitations of the tube itself: the thickness of the glass tube wall, the difficulty of forming a truly rectangular tube screen, and the like. Due to these and other factors, the multiple television tube displays have always suffered from dark matrix lines between adjacent television tubes that detract from the impact and definition of the total image.
A remedy for this drawback, also known in the prior art, involves the use of a plurality of flat lenses, each disposed adjacent to one of the television tubes and adapted to magnify the image therefrom sufficiently to mask the dark edges of the tubes. Although this approach is effective, it invites the leakage or spillover of image light from adjacent television tubes, especially at viewing angles eccentric to the central portion of the display. Thus such displays are limited in viewing angle, and care must be taken to place the viewers within the limited viewing space.
Another drawback of large format matrix video displays is the sheer complexity of the matrix itself. Assembling and supporting up to several hundred television tubes in a matrix is a difficult engineering task, in terms of mechanical support of the tubes in such close proximity, heat dissipation, wiring routing, and maintenance and replacement of individual tubes. These problems have not been addressed in the prior art, resulting in high cost and extensive labor required to build and sustain a large format matrix display.